Superconductivity in sputtered CuMO6S8

Samples were prepared by melting the metals, followed by annealing to various temperatures. The result was a structurally weak material. Sputtered films on sapphire substrates were prepared and studied. The substrates give the films mechanical strength and permit easy attachment of electrical leads. Materials were characterized by X-ray diffraction, electron microscopy, electrical resistance vs. temperature, and critical current measurements. Some of the results on CuMo6S8 are presented

Self-organization in porous 6H–SiC

Pores in porous 6H–SiC were found to propagate first nearly parallel with the basal plane and gradually change direction and align with the c axis. As a consequence, well-defined columnar pores were formed. It was shown that the rate of change of propagation directions was influenced by the etching parameters, such as hydrofluoric acid concentration and current density. Larger currents resulted in formation of larger pores. Pore sizes were found to increase with depth due to a decrease of the acid concentration. In addition, due to chemical etching effects, larger pore sizes were obtained close to the sample surface

Self-organization in porous 6H–SiC

Pores in porous 6H–SiC were found to propagate first nearly parallel with the basal plane and gradually change direction and align with the c axis. As a consequence, well-defined columnar pores were formed. It was shown that the rate of change of propagation directions was influenced by the etching parameters, such as hydrofluoric acid concentration and current density. Larger currents resulted in formation of larger pores. Pore sizes were found to increase with depth due to a decrease of the acid concentration. In addition, due to chemical etching effects, larger pore sizes were obtained close to the sample surface

Convolutional Neural Network for Seismic Phase Classification, Performance Demonstration over a Local Seismic Network

Over the past two decades, the amount of available seismic data has increased significantly, fueling the need for automatic processing to use the vast amount of information contained in such data sets. Detecting seismicity in temporary aftershock networks is one important example that has become a huge challenge because of the high seismicity rate and dense station coverage. Additionally, the need for highly accurate earthquake locations to distinguish between different competing physical processes during the postseismic period demands even more accurate arrival‐time estimates of seismic phase. Here, we present a convolutional neural network (CNN) for classifying seismic phase onsets for local seismic networks. The CNN is trained on a small dataset for deep‐learning purposes (411 events) detected throughout northern Chile, typical for a temporary aftershock network. In the absence of extensive training data, we demonstrate that a CNN‐based automatic phase picker can still improve performance in classifying seismic phases, which matches or exceeds that of historic methods. The trained network is tested against an optimized short‐term average/long‐term average (STA/LTA) based method (Rietbrock et al., 2012) in classifying phase onsets for a separate dataset of 3878 events throughout the same region. Based on station travel‐time residuals, the CNN outperforms the STA/LTA approach and achieves location residual distribution close to the ones obtained by manual inspection

Infrared response of multiple-component free-carrier plasma in heavily doped \u3ci\u3ep\u3c/i\u3e-type GaAs

Spectroscopic ellipsometry is used to measure the dielectric function of heavily doped p-type GaAs for wave numbers from 100 to 2000 cm-1. Due to partial filling of the heavy- and light-hole valence bands, heavy holes as well as light holes form a multiple-component plasma coupled with longitudinal optical phonons. Line-shape analysis of the infrared response allows differentiating between light- and heavy-hole contributions to the carrier plasma, and the results observed suggest nonparabolicity effects of the heavy- and light-hole valence bands in GaAs

Ground and space based optical analysis of materials degradation in low-Earth-orbit

There is strong interest in being able to accurately and sensitively monitor materials degradation in both ground-based and space-based environments. Two optical techniques for sensitive degradation monitoring are reviewed: spectroscopic ellipsometry and photothermal spectroscopy. These techniques complement each other in that ellipsometry is sensitive to atomically thin surface and subsurface changes, and photothermal spectroscopy is sensitive to local defects, pin-holes, subsurface defects, and delamination. Progress in applying these spectroscopies (both ex situ and in situ) to atomic oxygen degradation of space materials is reviewed

Ellipsometric study of InGaAs MODFET material

In(x)Ga(1-x)As based MODFET (modulation doped field effect transistor) material was grown by molecular beam epitaxy on semi-insulating InP substrates. Several structures were made, including lattice matched and strained layer InGaAs. All structures also included several layers of In(0.52)Al(0.48)As. Variable angle spectroscopic ellipsometry was used to characterize the structures. The experimental data, together with the calibration function for the constituent materials, were analyzed to yield the thickness of all the layers of the MODFET structure. Results of the ellipsometrically determined thicknesses compare very well with the reflection high energy electron diffraction in situ thickness measurements

APPLICATION OF INTERMEDIATE WAVELENGTH BAND SPECTROSCOPIC ELLIPSOMETRY TO IN-STU. REAL TIME FABRICATION OF MULTIPLE LAYER ALTERNATING HGHALOW REFRACTIVE INDEX FILTERS

Disclosed is application of oblique angle of incidence, reflection and/or transmission mode spectroscopic ellipsometry PSI and/or DELTA, (including combinations thereof and/or mathematical equivalents), vs. wavelength data over an intermediate wavelength band range around a pass or reject band, to monitor and/or control fabrication of multiple layer high/low refractive index band-pass, band-reject and varied attenuation vs. wavelength thin film interference filters, either alone or in combination with transmissive non-ellipsometric electromagnetic beam turning point vs. layer data obtained at an essentially normal angle of incidence

APPLICATIONOFSPECTROSCOPIC ELLIPSOMETRY TO IN-STU. REAL-TIME FABRICATION OF MULTIPLE LAYER ALTERNATING HIGH/LOW REFRACTIVE INDEX FILTERS

Disclosed is application of oblique angle of incidence, reflection and/or transmission mode spectroscopic ellipsometry PSI and/or DELTA, (including combinations thereof and/or mathematical equivalents), vs. wavelength data to monitor and/or control fabrication of multiple layer high/low refractive index band-pass, band-reject and varied attenuation vs. wavelength filters, either alone or in combination with transmissive non-ellipsometric electromagnetic beam turning point vs. layer data obtained at an essentially normal angle of incidence

Dielectric function of InGaAs in the visible

Measurements are reported of the dielectric function of thermodynamically stable In(x)Ga(1-x)As in the composition range 0.3 equal to or less than X = to or less than 0.7. The optically thick samples of InGaAs were made by molecular beam epitaxy (MBE) in the range 0.4 = to or less than X = to or less than 0.7 and by metal-organic chemical vapor deposition (MOCVD) for X = 0.3. The MBE made samples, usually 1 micron thick, were grown on semi-insulating InP and included a strain release structure. The MOCVD sample was grown on GaAs and was 2 microns thick. The dielectric functions were measured by variable angle spectroscopic ellipsometry in the range 1.55 to 4.4 eV. The data was analyzed assuming an optically thick InGaAs material with an oxide layer on top. The thickness of this layer was estimated by comparing the results for the InP lattice matched material, i.e., X = 0.53, with results published in the literature. The top oxide layer mathematically for X = 0.3 and X = 0.53 was removed to get the dielectric function of the bare InGaAs. In addition, the dielectric function of GaAs in vacuum, after a protective arsenic layer was removed. The dielectric functions for X = 0, 0.3, and 0.53 together with the X = 1 result from the literature to evaluate an algorithm for calculating the dielectric function of InGaAs for an arbitrary value of X(0 = to or less than X = to or less than 1) were used. Results of the dielectric function calculated using the algorithm were compared with experimental data